The present invention relates to a shut-off valve with a great turn-on time for fluids under high pressure.
Under high pressure, high pressure above 1,000 bar is understood. With such pressures sealing cones and sealing seats are always made of metal. The sealing seat is composed as a rule of a more or less sharp edge at the mouth of a valve housing bore hole. The sealing cone is pressed against it and thereby the required sealing action is obtained. The working fluid is water, mixed in some cases with additives.
In such valves, the indifferent conditions, especially with a valve which is always slightly open or in other words, with a small gap between the sealing cone and the sealing seat, lead fast to destruction of the sealing seat. The extrordinary high flow speed of rhe fluid in the sealing gap which takes place at a pressure above 1,000 bar, cause cavitation and material errosion. For unloading the sealing seat and obtaining a high actuation frequency (great turn-on time) it is advantageous to open the valve as fast as possible and to close it as fast as possible. These features lead, however, to enormously high pressure peaks in the hydraulic system in which the shut-off valve is incorporated. These pressure peaks lead to breakage in the pipe and hose conduits of the hydralic system.